Cattle farming is vital to the economy of the United States. Frequently, cattle are given access to ponds and streams for water. The relative impacts of cattle access in natural water sources on the periphyton community have been rarely investigated. Periphyton is the basis of the aquatic food web, and community composition can serve as a bioindicator of pollution. Thus, my objectives were to quantify the effects of cattle access in aquatic lentic systems on periphyton community structure and biovolume, identify taxa that were associated with cattle access, and identify abiotic mechanisms that might be driving assemblage changes. I conducted my research in 4 cattle-access (CA) and 4 no-access (NA) farm ponds on the University of Tennessee Plateau Research and Education Center from May 2005 – April 2006. Periphyton community composition and water quality were measured every 2 weeks using standard environmental monitoring procedures. I documented 181 new periphyton taxonomic records (7 phyla, 52 families, and 132 genera) in Cumberland County, Tennessee. Periphyton species richness was greatest in NA ponds. Mean biovolume of pollution-sensitive diatoms (e.g., Achnanthidium minutissimum, Cymbella sp., Eunotia sp., Fragilaria crotonensis and Tabellaria fenestrata) was greater in NA ponds. In contrast, pollution-tolerant diatoms (e.g., Gomphonema sp. and Navicula sp.) and non-diatoms (e.g., Oscillatoria sp. and Scenedesmus sp.) were more abundant in CA ponds. Turbidity, pH, conductivity, and concentrations of the total Kjeldahl nitrogen, total phosphorus, potassium, periphyton phosphorus, silicon, iron, magnesium and aluminum were greater in CA ponds. Thus, changes in water quality associated with cattle-access likely mediated changes in the periphyton community. Considering that changes in periphyton community composition can destabilize higher trophic levels, I recommend that cattle farmers take advantage of USDA conservation programs that provide funds for fencing cattle from watersheds and developing alternate water sources. My results also provide evidence that monitoring the periphyton community is a reliable technique to detect water pollution from cattle.

A novel tracer method has used 15N to label Escherichia coli and track the transport of bacteria, a common contaminant, through karst aquifers. Use of this method could provide valuable insight into the movement of bacteria in aquifers, which would help improve remediation methods and strategies. A wild strain of E. coli was isolated from the Cane Run/Royal Spring basin in the Inner Bluegrass region of Kentucky. The strain was serotyped O-:H- and virulence testing showed the strain did not have virulence factors of E. coli commonly pathogenic to humans. Five karst microcosms were filled with sterilized water collected from Royal Spring in Georgetown, Kentucky. Each microcosm was inoculated with wild-type E. coli, enriched in 15N, and incubated at 14° C for 130 days. The microcosms were periodically sampled for the concentration and nitrogen isotope composition of E. coli over 130 days. The E. coli survived at concentrations within one log of the average initial value of 5.62×1010 for the duration of the study. Statistical modeling showed no significant difference in δ15N values from day 1 and day 130. This strain is therefore recommended for traces in the Cane Run/Royal Spring basin.

Antibiotics are important to equine medicine, but can cause detrimental side-effects including reduced feed intake, allergic reactions, and diarrhea. Antibiotic-associated diarrhea (AAD) is attributed to disruption of the hindgut microflora, permitting proliferation of pathogenic microbes. The objectives were to evaluate the effects of antibiotics on beneficial fecal bacteria, AAD-associated pathogens, microbial species richness and fermentation. Horses were assigned to treatment groups: control (no antibiotics, n=6), trimethoprim-sulfadiazine (oral, n=6), or sodium ceftiofur (IM, n=6). Fecal samples were taken during adaptation (3 wk), antibiotic challenge (1 wk), and withdrawal (1 wk). Fecal cellulolytics decreased by >99% during challenge and did not recover during withdrawal (P < 0.0001). Lactobacilli decreased by >60% during challenge (P = 0.0453). Salmonella spp. increased 94% with trimethoprim-sulfadiazine challenge (P = 0.0115). There was no detectable Clostridium difficile during adaptation or in any control horse. C. difficile increased (P < 0.0001) when horses were challenged, and remained elevated 7 d after withdrawal. There was no effect of challenge on in vitro digestibility or microbial species richness as evaluated by denaturing gradient gel electrophoresis (P > 0.05). These results indicate that antibiotics can disrupt the normal flora and allow proliferation of pathogens, even without affecting digestibility and causing AAD.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 6 uppsatser.

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Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-06-19T18:29:46Z No. of bitstreams: 2 Dissertação - Ludimila Aparecida Cavalcante Wosnjuk Carvalho - 2014.pdf: 2513524 bytes, checksum: 5ad4e1e6478e62a6aee4bf01e2c6a7c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Cláudia Bueno (claudiamoura18@gmail.com) on 2017-07-07T18:07:01Z (GMT) No. of bitstreams: 2 Dissertação - Ludimila Aparecida Cavalcante Wosnjuk Carvalho - 2014.pdf: 2513524 bytes, checksum: 5ad4e1e6478e62a6aee4bf01e2c6a7c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-07T18:07:02Z (GMT). No. of bitstreams: 2 Dissertação - Ludimila Aparecida Cavalcante Wosnjuk Carvalho - 2014.pdf: 2513524 bytes, checksum: 5ad4e1e6478e62a6aee4bf01e2c6a7c6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-09-30 / Helicobacter pylori is a gran-negative bacteria known as the leading cause of gastritis, peptic ulcer, gastric lymphoma and tissue lymphoma associated to gastric mucosa, which are responsible for almost 9% of cancer deaths in the world. Its mode of transmission is unclear, but it is suggested that the oral-oral, fecal-oral routes in addition to transmission through contaminated food, water, human milk and through animals. Many of these transmission channels related with the water and, therefore, have given importance to develop methodologies capable of detecting bacteria in water samples, since the bacterium in an aquatic environment becomes a state coccoid (known to be viable but not culturable). Thus, the common detection methods based on culture are not as effective in these circumstances. The most widely used techniques in recent years for detecting Helicobacter pylori in water consist of filtration for the concentration of samples, DNA extraction and amplification of genetic material through the Polymerase Chain Reaction (PCR). The study objective was to reproduce these techniques with samples of treated water coming from the public supply of treated water system from the city of Goiânia - Goiás - Brazil. To this end, in partnership with SANEAGO (sanitation company of Goiás), 102 samples of treated water (accounting for 18 points of the distribution network supplied by Meia Ponte River) were collected and analyzed samples for the water temperature , associated with the storage environment, the local climate, the amount of residual chlorine and the presence of Helicobacter pylori DNA in the period from June to November 2013. Those samples were collected during the rainless period, the temperature ranged from 22 ° C, and 33 ° C and the water temperature between 21 ° C and 25 ° C. The residual chlorine was between 0.77 and 1.7. And no positive samples for the presence of DNA of Helicobacter pylori were found. It is therefore concluded the absence of Helicobacter pylori in the samples. / Helicobacter pylori é uma bactéria gran-negativa conhecida como a maior causadora de gastrite, úlcera péptica, linfoma gástrico, linfoma tecidual associado a mucosa gástrica, que são responsáveis por praticamente 9% das mortes por câncer no mundo. Seu modo de transmissão ainda não é claro, mas sugere-se as vias oral-oral, oral-fecal, além da transmissão por alimentos contaminados, por água contaminada, por leite materno e por animais. Muitas dessas vias de transmissão se relacionam com a água e, por isso, têm se dado importância ao desenvolvimento de metodologias capazes de detectar a bactéria em amostras de água, visto que em ambiente aquático a bactéria se transforma num estado cocoide (conhecido por ser viável, porém não cultivável). Desta maneira, os comuns métodos de detecção baseados em cultura não são tão eficazes nessas circunstâncias. As técnicas mais utilizadas nos últimos anos para detecção de Helicobacter pylori em água consistem em filtração para a concentração das amostras, extração de DNA e amplificação de material genético através da Reação em Cadeia da Polimerase (PCR). O objetivo do estudo foi reproduzir essas técnicas com amostras de água tratada advindas do sistema de abastecimento público de água tratada da cidade de Goiânia – Goiás – Brasil. Para tal, em parceria com a SANEAGO (empresa de saneamento de Goiás), 102 amostras de água tratada (representando 18 pontos da rede de distribuição abastecida pelo Rio Meia Ponte) foram coletadas e analisadas quanto a temperatura da água e do ambiente de estocagem, ao clima da região, ao valor de cloro residual e a presença de DNA de Helicobacter pylori entre os meses de junho à novembro de 2013. As amostras foram coletadas no período sem chuvas da região, a temperatura ambiente variou entre 22°C e 33°C e a temperatura da água entre 21°C e 25°C. O cloro residual foi entre 0,77 e 1,7. E não foram encontradas amostras positivas com relação a presença de DNA de Helicobacter pylori. Concluiu-se assim a ausência de Helicobacter pylori nas amostras analisadas.

Pseudomonas syringae produz núcleos de gelo biológicos de grande eficiência. Bioaerossóis destas células tem potencial de participar na glaciação de nuvens, podendo influenciar a precipitação. Foram estudadas como as condições as quais P. syringae está sujeita em suspensão na atmosfera afetam sua sobrevivência e sua atividade de nucleação de gelo. Duas cepas foram testadas, e ambas apresentaram baixa tolerância ao UV-C e ao UV-B, mas exibiram uma maior resistência quando expostas a um espectro semelhante ao encontrado no ambiente. A atividade de congelamento de uma das cepas (pv. syringae) não foi afetada pelo UV, enquanto que para a outra (pv. garcae) houve uma redução moderada. Em resposta à dessecação, pv. garcae foi substancialmente mais resistente que pv. syringae. Isto também afetou a nucleação de gelo das cepas. Em ensaios adicionais, estas bactérias foram expostas em um voo de balão estratosférico, e a uma simulação em laboratório das condições no topo da troposfera. Nestes dois experimentos, sobreviventes protegidos do UV foram recuperados. / Pseudomonas syringae produces biological ice nuclei of great efficiency. Bioaerosols of these cells have the potential to take part in cloud glaciation, possibly influencing the precipitation. It was studied how the conditions to which P. syringae is subjected while in suspension in the atmosphere affect its survival and its ice nucleation activity. Two strains were tested, and both showed a low tolerance to UV-C and UV-B, but exhibited a higher resistance when exposed to a spectrum similar to the one found in the environment. The freezing activity of one of the strains (pv. syringae) was not affected by the UV, while that for the other (pv. garcae) there was a moderate reduction. In response to desiccation, pv. garcae was substantially more resistant than pv. syringae. This also affected the ice nucleation by the strains. In additional assays, these bacteria were exposed in a stratospheric balloon flight, and to a laboratory simulation of the conditions at the top of the troposphere. After these two experiments, survivors protected from the UV were recovered.